1. Technical Field
The present disclosure relates to surgical instruments. More particularly, the present disclosure relates to a method, system, and apparatus for identifying surgical instruments using capacitive elements.
2. Discussion of Related Art
Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ultrasonic, microwave, cryogenic, heat, laser, etc.) are used to treat tissue. One such type of energy used to treat tissue is electrosurgical energy. Electrosurgery is the application of electricity and/or electromagnetic energy to cut, dissect, ablate, coagulate, cauterize, seal or otherwise treat biological tissue during a surgical procedure. Generally, electrosurgery utilizes an electrosurgical generator operable to output energy and active and return electrodes that are electrically connected via a cable assembly to the generator.
In bipolar electrosurgery, one of the electrodes of a hand-held instrument functions as the active electrode and another electrode of the hand-held instrument functions as the return electrode. The return electrode is placed in close proximity to the active electrode such that an electrical circuit is formed between the two electrodes (e.g., electrosurgical forceps). Bipolar electrosurgical techniques and instruments can be used to coagulate blood vessels or tissue, e.g., soft tissue structures, such as lung, brain, and intestine. A surgeon can cauterize, coagulate, desiccate tissue, or simply reduce or slow bleeding by controlling the intensity, frequency, and duration of the electrosurgical energy applied between the electrodes and through the tissue. In order to achieve the desired surgical effects without causing unwanted charring of tissue at the surgical site or causing collateral damage to adjacent tissue, e.g., thermal spread, the output from the electrosurgical generator is controlled, e.g., power, waveform, voltage, current, pulse rate, etc.
In monopolar electrosurgery, the active electrode is typically part of the surgical instrument held by the surgeon that is applied to the tissue to be treated. A patient return pad having one or more return electrodes is placed remotely from the active electrode to carry the electrosurgical energy back to the generator and safely disperse current applied by the active electrode. The return electrodes usually have a large patient-contact surface area to minimize heating at that site. Heating is caused by high current densities that directly depend on the surface area. A larger surface contact area results in lower localized heat intensity. The size of the return electrodes is typically chosen based upon assumptions of the maximum current utilized during a particular surgical procedure and the generator's duty cycle (i.e., the percentage of time the generator is on).
Electrosurgical devices utilizing electricity and/or electromagnetic energy have been developed for a variety of uses and applications. One type of energy-based treatment of tissue is microwave-energy based treatment. Typically, microwave apparatus for use in surgical procedures include a microwave generator that functions as an energy source, and a microwave surgical instrument (e.g., microwave ablation probe) having an antenna assembly for directing energy to the target tissue. The microwave generator and surgical instrument are typically operatively coupled by a cable assembly having a plurality of conductors for transmitting microwave energy from the generator to the instrument, and for communicating control, feedback and identification signals between the instrument and the generator.
There are several types of microwave surgical instruments (e.g., microwave probes) in use, e.g., monopole, dipole, and helical. One type is a monopole antenna probe, which consists of a single, elongated microwave conductor exposed at the end of the probe. The probe is typically surrounded by a dielectric sleeve. The second type of microwave probe commonly used is a dipole antenna, which typically consists of a coaxial construction having an inner conductor and an outer conductor with a dielectric junction separating a portion of the inner conductor. In the monopole and dipole antenna probes, microwave energy generally radiates perpendicularly from the axis of the conductor.